The technique of using engineered T cells against cancerous cells may be about to explode ever more than it has already. One of the hardest parts of getting this process scaled up has been the need to extract each patient's own T cells and reprogram them. But in a new report in Nature Biotechnology, a team at Sloan-Kettering shows that they can raise cells of this type from stem cells, which were themselves derived from T lymphocytes from another healthy donor. As The Scientist puts it:
Sadelain’s team isolated T cells from the peripheral blood of a healthy female donor and reprogrammed them into stem cells. The researchers then used disabled retroviruses to transfer to the stem cells the gene that codes for a chimeric antigen receptor (CAR) for the antigen CD19, a protein expressed by a different type of immune cell—B cells—that can turn malignant in some types of cancer, such as leukemia. The receptor for CD19 allows the T cells to track down and kill the rogue B cells. Finally, the researchers induced the CAR-modified stem cells to re-acquire many of their original T cell properties, and then replicated the cells 1,000-fold.
“By combining the CAR technology with the iPS technology, we can make T cells that recognize X, Y, or Z,” said Sadelain. “There’s flexibility here for redirecting their specificity towards anything that you want.”
You'll note the qualifications in that extract. The cells that are produced in this manner aren't quite the same as the ones you'd get by re-engineering a person's own T-cells. We may have to call them "T-like" cells or something, but in a mouse lymphoma model, they most certainly seem to do the job that you want them to. It's going to be harder to get these to the point of trying them out in humans, since they're a new variety of cell entirely, but (on the other hand) the patients you'd try this in are not long for this world and are, in many cases, understandably willing to try whatever might work.
Time to pull the camera back a bit. It's early yet, but these engineered T-cell approaches are very impressive. This work, if it holds up, will make them a great easier to implement. No doubt, at this moment, there are Great Specific Antigen Searches underway to see what other varieties of cancer might respond to this technique. And this, remember, is not the only immunological approach that's showing promise, although it must be the most dramatic.
So. . .we have to consider a real possibility that the whole cancer-therapy landscape could be reshaped over the next decade or two. Immunology has the potential to disrupt the whole field, which is fine by me, since it could certainly use some disruption, given the state of the art. Will we look back, though, and see an era where small-molecule therapies gave people an extra month here, an extra month there, followed by one where harnessing the immune system meant sweeping many forms of cancer off the board entirely? Speed the day, I'd say - but if you're working on those small-molecule therapies, you should keep up with these developments. It's not time to consider another line of research, not yet. But the chances of having to do this, at some point, are not zero. Not any more.